Potomac Photonics, Inc.

Nicholas Doudoumopoulos

Paul Wickboldt

C Paul Christensen

Paul Christensen

The manufacturing methodology to produce polycrystalline silicon in time and cost efficient manner uses a spatially selective crystallization approach to greatly reduce the amount of energy delivered to the work surface. The amorphous silicon film is subjected to laser radiation substantially exclusively at localized areas where TFTs are to be formed. The source of radiation is a copper vapor laser which produces a highly stable radiation in a visible spectrum with an energy sufficient to convert amorphous silicon into polysilicon in 1-3 shots. The optic system delivers the homogenized, conditioned and focused laser beam to the area of interest in a controlled manner. Single or multi-laser beam arrangements, as well as different shapes and sizes of laser beam spots are contemplated.

Method and system for spatially selective crystallization of amorphous silicon

A method utilizing spatially selective laser doping for irradiating predetermined portions of a substrate of a semiconductor material is disclosed. Dopants are deposited onto the surface of a substrate. A pulsed, visible beam is directed to and preferentially absorbed by the substrate only in those regions requiring doping. Spatial modes of the incoherent beam are overlapped and averaged, providing uniform irradiation requiring fewer laser shots. The beam is then focused to the predetermined locations of the substrate for implantation or activation of the dopants. The method provides for scanning and focusing of the beam across the substrate surface, and irradiation of multiple locations using a plurality of beams. The spatial selectivity, combined with visible laser wavelengths, provides greater efficiency in doping only desired substrate regions, while reducing the amount of irradiation required. Savings in cost and manufacturing throughput can be achieved, particularly with respect to doping poly-crystalline silicon.

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Garrett Park, MD, United States of America

Nicholas Doudoumopoulos